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All-Digital Power Amplifier Based on Pulse-Width Modulation

An all-digital power amplifier capable of driving a loudspeaker at high-power levels is analyzed and implemented. The amplifier is based on linearized pulse-width modulation (LPWM). The LPWM amplifier has an efficiency of >90% at eight-times oversampling. It is shown that the distortion generated by the output stage limits the system performance. The LPWM amplifier is compared with a Sigma-Delta modulator based amplifier.